Review: Nutrient and energy supply in monogastric food producing animals with reduced environmental and climatic footprint and improved gut health

With more efficient utilisation of dietary nutrients and energy, diversified production systems, modifications of diet composition with respect to feedstuffs included and the use of free amino acids, the negative impact of animal food production on the environment and climate can be reduced. Accurate requirements for nutrients and energy for animals with differing physiological needs, and the use of robust and accurate feed evaluation systems are key for more efficient feed utilisation. Data on CP and amino acid requirements in pigs and poultry indicate that it should be possible to implement indispensable amino acid-balanced diets with low- or reduced-protein content without any reduction in animal performance. Potential feed resources, not competing with human food security, can be derived from the traditional food- and agroindustry, such as various waste streams and co-products of different origins. In addition, novel feedstuffs emerging from aquaculture, biotechnology and innovative new technologies may have potential to provide the lack of indispensable amino acids in organic animal food production. High fibre content is a nutritional limitation of using waste streams and co-products as feed for monogastric animals as it is associated with decreased nutrient digestibility and reduced dietary energy values. However, minimum levels of dietary fibre are needed to maintain the normal physiological function of the gastro-intestinal tract. Moreover, there may be positive effects of fibre in the diet such as improved gut health, increased satiety, and an overall improvement of behaviour and well-being.

Age Rather Than Supplementation with Oat β-Glucan Influences Development of the Intestinal Microbiota and SCFA Concentrations in Suckling Piglets

The effects of early supplementation with oat β-glucan during the suckling period on piglet gut microbiota composition, concentrations of short-chain fatty acids, and gut physiological markers were assessed. Fifty piglets from five litters, balanced for sex and birth weight, were divided within litters into two treatment groups: β-glucan and control. Piglets in the β-glucan group received the supplement three times/week from day 7 of age until weaning. Rectal swab samples were collected from 10 piglets per treatment group (balanced across litters) from week 1 to week 4, and plasma samples were collected at 1, 3, and 4 weeks of age. Additional samples of intestinal tissues and jugular and portal vein plasma were collected from 10 animals at weaning (one per treatment group and litter). The concentrations of short-chain fatty acids in plasma and the microbiota composition in rectal swabs were mainly influenced by piglet age, rather than the supplement. There were significant differences in microbiota composition between litters and several correlations between concentrations of short-chain fatty acids in plasma and specific microbial taxa in rectal swabs. Overall, β-glucan supplementation did not have any clear impact on the gut environment in suckling piglets, whereas a clear age-related pattern emerged.

Effects of provision of water and nesting material on reproductive performance of native Moo Lath pigs in Lao PDR

This study investigated the effect of providing extra water and nesting material to Moo Lath sows on piglet survival and growth. Three treatments were evaluated in a randomized block design with six sows/treatment. In the Control treatment, sows were not provided with nesting material or extra water apart from that included in the feed (conventional smallholder practice). In treatment NM, nesting material was provided 1–2 days before expected farrowing. In treatment NMW, nesting material as in NM and extra water were provided ad libitum throughout the study. Data on sow feed and water intake, plasma protein concentration (TPP), body weight, and re-mating period, and on litter size, body weight, and survival of piglets, were collected for two reproduction cycles. NMW sows had higher water intake than Control and NM sows (14.7, 4.5, and 4.5 L/day, respectively, SE = 0.2). The weight loss from 2 weeks prior to farrowing until weaning was smaller in NMW than in NM and Control sows (16.0, 23.8, and 22.9 kg, respectively, SE = 0.9). TPP dropped from farrowing until 21 days of lactation in NMW sows, whereas it increased or was unchanged in NM and Control sows. The re-mating period was shorter and the number of litters/year was higher in NMW than in Control and NM sows (2.2, 2.0, and 2.0, respectively, SE = 0.01). Piglet mortality was lower in NMW than in Control and NM (9.5, 43.9, and 26.7%, respectively, SE = 4.9). Piglets in NMW were heavier at weaning and had higher daily weight gain than Control and NM piglets. It was concluded that providing water ad libitum and nesting material improved piglet survival and growth, and that providing water ad libitum improved sow physiological and reproductive fitness. However, provision of nesting material without access to ad libitum water might increase susceptibility to heat stress in sows.

Fecal microbiome of growing pigs fed a cereal based diet including chicory (Cichorium intybus L.) or ribwort (Plantago lanceolata L.) forage

Background

The purpose of this study was to investigate how inclusion of chicory forage or ribwort forage in a cereal-based diet influenced the fecal microbial community (microbiome) in newly weaned (35 days of age) piglets. The piglets were fed a cereal-based diet without (B) and with inclusion (80 and 160 g/kg air-dry forage) of vegetative shoots of chicory (C) and leaves of ribwort (R) forage in a 35-day growth trial. Fecal samples were collected at the start (D0), 17 (D17) and 35 (D35) days after weaning and profiles of the microbial consortia were generated using terminal restriction fragment length polymorphism (T-RFLP). 454-FLX pyrosequencing of 16S rRNA gene amplicons was used to analyze the microbial composition in a subset of the samples already analyzed with T-RFLP.

Results

The microbial clustering pattern was primarily dependent on age of the pigs, but diet effects could also be observed. Lactobacilli and enterobacteria were more abundant at D0, whereas the genera Streptococcus, Treponema, Clostridium, Clostridiaceae1 and Coprococcus were present in higher abundances at D35. Pigs fed ribwort had an increased abundance of sequences classified as Treponema and a reduction in lactobacilli. However, the abundance of Prevotellaceae increased with age in on both the chicory and the ribwort diet. Moreover, there were significant correlations between the abundance of Bacteroides and the digested amount of galactose, uronic acids and total non-starch polysaccharides, and between the abundance of Bacteroidales and the digested amount of xylose.

Conclusion

This study demonstrated that both chicory and ribwort inclusion in the diet of newly weaned pigs influenced the composition of the fecal microbiota and that digestion of specific dietary components was correlated with species composition of the microbiota. Moreover, this study showed that the gut will be exposed to a dramatic shift in the microbial community structure several weeks after weaning.

Effects of Lactobacillus johnsonii and Lactobacillus reuteri on gut barrier function and heat shock proteins in intestinal porcine epithelial cells

Heat shock proteins (HSPs) are a set of highly conserved proteins that can serve as intestinal gate keepers in gut homeostasis. Here, effects of a probiotic, Lactobacillus rhamnosus GG (LGG), and two novel porcine isolates, Lactobacillus johnsonii strain P47-HY and Lactobacillus reuteri strain P43-HUV, on cytoprotective HSP expression and gut barrier function, were investigated in a porcine IPEC-J2 intestinal epithelial cell line model. The IPEC-J2 cells polarized on a permeable filter exhibited villus-like cell phenotype with development of apical microvilli. Western blot analysis detected HSP expression in IPEC-J2 and revealed that L. johnsonii and L. reuteri strains were able to significantly induce HSP27, despite high basal expression in IPEC-J2, whereas LGG did not. For HSP72, only the supernatant of L. reuteri induced the expression, which was comparable to the heat shock treatment, which indicated that HSP72 expression was more stimulus specific. The protective effect of lactobacilli was further studied in IPEC-J2 under an enterotoxigenic Escherichia coli (ETEC) challenge. ETEC caused intestinal barrier destruction, as reflected by loss of cell–cell contact, reduced IPEC-J2 cell viability and transepithelial electrical resistance, and disruption of tight junction protein zonula occludens-1. In contrast, the L. reuteri treatment substantially counteracted these detrimental effects and preserved the barrier function. L. johnsonii and LGG also achieved barrier protection, partly by directly inhibiting ETEC attachment. Together, the results indicate that specific strains of Lactobacillus can enhance gut barrier function through cytoprotective HSP induction and fortify the cell protection against ETEC challenge through tight junction protein modulation and direct interaction with pathogens.

Effect of Fibre Level and Fibre Source on Gut Morphology and Micro-environment in Local (Mong Cai) and Exotic (Landrace×Yorkshire) Pigs

The effect of genotype, fibre level and fibre source on gut morphology, environment and microflora was studied using 18 Mong Cai (MC) and 18 Landrace×Yorkshire (LY) pigs, aged around 60 d. The diets were based on maize, rice bran, soybean meal, fish meal and soybean oil, and cassava residue (CR) or brewer's grain (BG) as fibrous ingredient sources in the high-fibre diets (HF). A low-fibre diet (LF), containing around 200 g NDF/kg dry matter (DM), was formulated without CR and BG as feed ingredients. The HF diets (HF-CR and HF-BG) were formulated to contain around 270 g NDF/kg DM. The experiment was arranged according to a 2×3 factorial completely randomized design with six replications, and lasted 30 d. Crypt density in ileum was lowest (p<0.05) and villus height in jejunum and ileum were the greatest (p<0.05) in pigs fed diet HF-BG. Villus width in ileum was greatest in pigs fed diets HF-CR and HF-BG (p<0.05). Lactic acid bacteria (LAB) counts in stomach were greatest (p<0.05) and E. coli counts in ileum and colon were lowest (p<0.05) in pigs fed diet HF-CR. The concentration of total organic acids in ileum, caecum and colon were greatest (p<0.05), and pH in ileum and colon were lowest (p<0.05) in pigs fed diet HF-CR. Crypt density in ileum was lowest, and villus height in ileum and villus width in jejunum and ileum was greatest in LY pigs (p<0.05). LAB counts in stomach and ileum were greatest, and E. coli counts in ileum were lowest in MC pigs (p<0.05). The concentration of total organic acids in ileum, caecum and colon were greatest (p<0.05) and pH lowest (p<0.05) in MC pigs.

Expression of heat shock proteins 27 and 72 correlates with specific commensal microbes in different regions of porcine gastrointestinal tract

The gastrointestinal (GI) tract of mammals is inhabited by trillions of microorganisms, resulting in exceedingly complex networking. The interaction between distinct bacterial species and the host immune system is essential in maintaining homeostasis in the gut ecosystem. For instance, the gut commensal microbiota dictates intestinal mucosa maturation and its abundant immune components, such as cytoprotective heat shock proteins (HSP). Here we examined physiological expression of HSP in the normal porcine GI tract and found it to be gut region- and cell type-specific in response to dietary components, microbes, and microbial metabolites to which the mucosa surface is exposed. Correlations between HSP72 expression and ileal Lactobacillus spp. and colonic clostridia species, and between HSP27 expression and uronic acid ingestion, were important interplays identified here. Thus this study provides novel insights into host-microbe interactions shaping the immune system that are modifiable by dietary regime.

Fiber effects in nutrition and gut health in pigs

Dietary fiber is associated with impaired nutrient utilization and reduced net energy values. However, fiber has to be included in the diet to maintain normal physiological functions in the digestive tract. Moreover, the negative impact of dietary fiber will be determined by the fiber properties and may differ considerably between fiber sources. Various techniques can be applied to enhance nutritional value and utilization of available feed resources. In addition, the extent of fiber utilization is affected by the age of the pig and the pig breed. The use of potential prebiotic effects of dietary fiber is an attractive way to stimulate gut health and thereby minimize the use of anti-microbial growth promoters. Inclusion of soluble non-starch polysaccharides (NSP) in the diet can stimulate the growth of commensal gut microbes. Inclusion of NSP from chicory results in changes in gut micro-environment and gut morphology of pigs, while growth performance remains unaffected and digestibility was only marginally reduced. The fermentation products and pH in digesta responded to diet type and were correlated with shifts in the microbiota. Interestingly, fiber intake will have an impact on the expression of intestinal epithelial heat-shock proteins in the pig. Heat-shock proteins have an important physiological role in the gut and carry out crucial housekeeping functions in order to maintain the mucosal barrier integrity. Thus, there are increasing evidence showing that fiber can have prebiotic effects in pigs due to interactions with the gut micro-environment and the gut associated immune system.

Chicory (Cichorium intybus L.) and cereals differently affect gut development in broiler chickens and young pigs

Dietary fiber, resistant to host-mediated digestion in the small intestine due to lack of endogenous enzymes, impacts many facets of animal health and is associated with gut development especially in young monogastrics. Furthermore, it can be used as in-feed antibiotic alternative. Chicory (Cichorium intybus L.) forage with high content of pectin (uronic acids as building blocks) is a novel class of dietary fiber that is chemically different from cereal grains (with high content of arabinoxylans). In the present study, we investigated effects of dietary inclusion of chicory forage on digestibility, gut morphology and microbiota in broilers and young pigs. In the chicken experiment, 160 1-d old broiler chicks were fed 3 nutritionally balanced diets for 30 d including a cereal-based diet and 2 diets with part of the cereals substituted with 60 and 120 g/kg chicory forage (CF60 and CF120), whereas in the pig experiment, 18 seven-wk old Yorkshire pigs were fed 3 diets for 18 d including a cereal-based diet and 2 diets with 80 and 160 g/kg chicory forage inclusion (CF80 and CF160). Our results showed that young pigs were capable to utilize chicory forage well with higher total tract apparent digestibility (TTAD) of all fiber fractions, particularly uronic acid, compared with the control (P < 0.01). In contrast, a decreased TTAD of all fiber fractions was observed in chickens fed on diet CF120 (P < 0.05). Moreover, diet induced changes in gut morphology were observed in the large intestine of chickens. The alteration of cecal mucosal thickness was further positively correlated with TTAD of non-starch polysaccharides (NSP) and its constituent sugars (P < 0.05). In addition, in pigs, terminal restriction fragment length polymorphism (T-RFLP) analysis of intestinal microbiota revealed substantial dietary effects (cereal control diet vs. chicory forage inclusion) on the relative abundance of 2 dominant bacterial phylotypes (Prevotella sp. vs. Roseburia sp.) respectively (P < 0.05). In conclusion, our data showed that chicory forage (Cichorium intybus L.), a novel dietary fiber source in animal nutrition, have potential beneficial properties as fiber ingredient in diets for both pigs and chickens.

Ileal and total tract digestibility of wet and dried wheat distillers grain products in growing pigs

The apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients were evaluated in 2 commercially available products: wheat (Triticum aestivum) wet distillers grain with solubles (WDGS) and wheat dried distillers grain with solubles (DDGS). Two diets included (DM basis) 50% basal diet with either 50% WDGS (W) or 50% DDGS (D). The basal diet included corn (Zea mays) starch, sugar, vitamins, and minerals. Seven castrated male pigs with post valve T-cecum cannulas were fed the diets according to a changeover design during two 14-d periods. In a pre- and postperiod, casein was given as the only protein source with the basal diet to estimate endogenous losses of N and AA for calculation of standardized ileal digestibility (SID). The AID of OM did not differ between diets, but ATTD of OM was higher (P < 0.05) for diet W. The AID (76.2 vs. 68.9%), SID, and ATTD of CP was higher (P < 0.05) in diet W than diet D. The SID for Lys (75.7 vs. 51.8%) and Met (75.8 vs. 70.1%) was higher (P < 0.01) in WDGS than DDGS. In conclusion, drying of wheat distillers grain products can markedly lower ileal digestibility of Lys and Met whereas negative effects on energy value are small.

Effect of replacing soybean protein by taro leaf (Colocasia esculenta (L.) Schott) protein on growth performance of exotic (Landrace × Yorkshire) and native (Moo Lath) Lao pigs

The impact of replacing soybean crude protein (CP) with CP from ensiled taro leaves (ET) on growth performance, carcass traits, and organ weights in Landrace × Yorkshire (LY) and Moo Lath (ML) Lao pigs was studied. Twenty-four castrated male pigs, 12 of each breed, were allocated to the treatments according to a completely randomized 3 × 2 factorial (three levels of ET × two breeds) arrangement with four pigs per treatment. The pigs were kept in individual pens and were fed at 4 % dry matter of body weight for 105 days. The control diet (ET0) was formulated with soybean meal as the main CP source, and in the other two diets, soybean CP was replaced to 25 % (ET25) and 50 % (ET50), respectively, with CP from ensiled taro leaves. Calculated metabolizable energy intake decreased with increasing replacement of soybean CP in the diet, while dry matter intake (DMI), CP intake (CPI), average daily gain (ADG), and feed conversion ratio (FCR) were unaffected. Carcass weight, back fat thickness, and dressing percentage were unaffected by soybean CP replacement, while organ weights (except for spleen) increased (P < 0.001) when soybean CP was replaced by CP from ensiled taro leaves in the diet. LY pigs had higher (P < 0.001) DMI, CPI, and ADG and better (P < 0.001) FCR than ML pigs. LY pigs had higher carcass weight (P < 0.001), lower back fat thickness (P < 0.001), and higher organ weights (P < 0.05-0.001) than the ML pigs. In conclusion, taro leaf silage can replace up to 50 % of soybean CP in the diet of growing Lao LY and ML pigs without negative effects on performance and carcass traits.

Digestibility of fibre sources and molecular weight distribution of fibre fractions in ileal digesta of growing pigs

Seven post-valve T-caecum cannulated growing pigs were used in a change-over experiment with four diets and four 14-day periods to evaluate the total tract apparent digestibility (TTAD) and the ileal apparent digestibility (IAD) of diets with inclusion of chicory forage (CFO), sugar beet pulp (SBP), wheat bran (WB) and grass meal (GM), as well as the TTAD of the mentioned fibre sources. Moreover, this experiment evaluated the molecular weight distribution of soluble non-starch polysaccharide (NSP) fractions in diet and ileal digesta from pigs fed the CFO and SBP diets. The experimental diets were balanced to have similar NSP content and compromised of one part of the basal diet and one part of the four fibre sources (CFO, SBP, WB and GM). In addition, all pigs were fed the basal diet during a 14-day period before and after the experimental periods. Diet affected the TTAD of all dietary components except glucose. The TTAD of organic matter (OM) was higher for Diet SBP than for Diets WB and CFO, showing both were higher than Diet GM. The TTAD of NSP was higher for Diet SBP than Diets WB and GM. The IAD of OM was higher in Diet SBP than in the other diets. The IAD of NSP was lower in Diet WB than in the other diets. The TTAD of OM and energy of CFO was 0.43 ± 0.04 (standard error), which is similar to that reported for commonly used forage crops. The molecular weight distribution in ileal digesta showed different distributions between Diets CFO and SBP as well as between digesta from pigs fed these diets.

Molecular weight distribution of soluble fiber fractions and short chain fatty acids in ileal digesta of growing pigs

The effect of dietary fiber source on molecular weight (MW) distribution of soluble fiber fractions and short chain fatty acids (SCFA) in ileal digesta of 7 post valve T-cecum (PVTC) cannulated growing pigs was studied. Pigs were fed semisynthetic diets with sugar beet (Beta vulgaris) pulp (SBP) or chicory (Cichorium intybus) forage (CFO) as fiber sources of which the soluble nonstarch polysaccharide (NSP) fraction originated mainly from pectin. Three MW intervals were selected-large MW (MWL): 10,000,000 to 1,000,000 g/mol, medium MW (MWM): 1,000,000 to 200,000 g/mol, and small MW (MWS): 200,000 to 10,000 g/mol-and the relative distribution (% of total) of molecules in each interval was calculated. The MWM fraction was higher (P < 0.05) in ileal digesta of pigs fed diet SBP and the MWS fraction was higher (P < 0.05) in ileal digesta of pigs fed diet CFO. The mole/100 mole of propionic acid (HPr) was higher (P < 0.010) in pigs fed diet SBP whereas pigs fed diet CFO had higher (P < 0.010) mole/100 mole of acetic acid (HAc). The proportion of the MWL and MWM fractions in ileal digesta were negatively correlated to HAc (r = -0.52, P = 0.05, and r = -0.62, P = 0.02, respectively). The proportion of MWM in ileal digesta was positively correlated to HPr (r = 0.83; P = 0.001) whereas MWS and HPr were negatively correlated (r = -0.76; P = 0.002). In conclusion, the bacterial degradation of the soluble NSP fraction is selective and MW distribution may explain differences in SCFA production.

Expression of heat shock protein 27 in gut tissue of growing pigs fed diets without and with inclusion of chicory fiber

The physiological expression of cytoprotective heat shock protein 27 (Hsp27) in the gut was investigated in eighteen 7-wk-old pigs fed one of 3 fiber-rich diets for 18 d. The diets were a cereal-based control diet and a cereal-based diet with inclusion of either 80 g/kg chicory forage (CF80) or chicory root (CR80). Immunohistochemical staining showed that Hsp27 was expressed in all the samples from ileum and colon. The expression was most intensive in the apical intestinal epitheliums in close contact with luminal contents and lighter in crypt cells. The ileal Peyer's patches showed a strong expression of Hsp27, which was highly correlated with Hsp27 expression in the ileal epithelial cells (P = 0.003). The frequency of ileal Hsp27 expression with the most intensive staining was distributed higher in pigs fed chicory forage diet (CF80, 25%) followed by chicory root diet (CR80, 16.7%) and the control (11.1%). In proximal colon, the frequency of expression showed a similar pattern for the different diets. The intestinal microbiota profile was characterized with the intention to find correlations to heat shock protein (Hsp) expression in pig gastrointestinal (GI) tract and showed that the distal ileum and proximal colon encompass its own unique microbial profile. However, no significant relationship was found between gut microbiota diversity and Hsp27 expression. These indicate that Hsp27 expression in the porcine gut could be associated with specific dietary fiber components but not the overall microbiota diversity.

Effect of replacing soybean protein with protein from ensiled stylo (Stylosanthes guianensis (Aubl.) Sw. var. guianensis) on growth performance, carcass traits and organ weights of exotic (Landrace × Yorkshire) and native (Moo Lath) Lao pigs

The present study examined the impact of replacing crude protein (CP) from soybean with CP from ensiled stylo (ES) on growth performance, carcass traits and organ weights in Landrace × Yorkshire (LY) and Moo Lath (ML) native Lao pigs. Twenty-four castrated male pigs, 12 of each breed, were allocated to the diet treatments according to a completely randomised 3 × 2 factorial (three ES levels × two breeds) arrangement, with four pigs per diet treatment. Pigs were kept in individual pens and fed at 4 % dry matter of body weight for 98 days. The control diet was formulated with soybean meal as the main CP source, and in the other two experimental diets, CP from soybean was replaced at 25 % (ES25) and 50 % (ES50) by CP from ES. Calculated metabolisable energy intake decreased with ES50 diet, while dry matter intake (DMI) and CP intake (CPI) were the highest in ES25 diet (P < 0.001). Overall, average daily gain (ADG) and feed conversion ratio (FCR) were unaffected by diet treatments. Carcass weight, backfat thickness and dressing percentage were unaffected by soybean CP replacement, while the weights of lung, large intestine and stomach were higher (P < 0.001) when 25 % of soybean CP was replaced by CP from ES. LY pigs had higher (P < 0.001) DMI, CPI and ADG and poorer (P < 0.001) FCR than ML pigs. LY pigs had higher carcass weight (P < 0.001), lower backfat thickness (P < 0.001) and higher organ weight (P < 0.001) than ML pigs, except for small intestine weight, where there was no difference between the LY and ML pigs (P > 0.05). In conclusion, ES can replace up to 50 % of soybean CP in the diet of growing Lao LY and ML pigs without negative effects on performance and carcass traits.

Impact of chicory inclusion in a cereal-based diet on digestibility, organ size and faecal microbiota in growing pigs

A total of 30 7-week-old pigs were used to evaluate the effects of chicory inclusion on digestibility, digestive organ size and faecal microbiota. Five diets were formulated: a cereal-based control diet and four diets with inclusion of 80 and 160 g/kg chicory forage (CF80 and CF160), 80 g/kg chicory root (CR80) and a mix of 80 g/kg forage and 80 g/kg chicory root (CFR). Generally, the pigs showed a high growth rate and feed intake, and no differences between the different diets were observed. The coefficients of total tract apparent digestibility (CTTAD) of energy, organic matter and CP did not differ between the control and CF80, whereas they were impaired in diet CF160. The CTTAD of non-starch polysaccharides and especially the uronic acids were higher (P < 0.05) with chicory inclusion, with highest (P < 0.05) values for diet CF160. Coliform counts were lower and lactobacilli : coliform ratio was higher (P < 0.05) in diet CFR than in the control. Global microbial composition was investigated by terminal restriction fragment length polymorphism combined with cloning and sequencing. Analysis of gut microbiota pattern revealed two major clusters where diet CF160 differed from the control and CR80 diet. Chicory forage diets were correlated with an increased relative abundance of one species related to Prevotella and decreased abundance of two other species related to Prevotella. For diet CFR, the relative abundance of Lactobacillus johnsonii was higher than in the other diets. This study shows that both chicory forage and root can be used as fibre sources in pig nutrition and that they modulate the composition of the gut microbiota differently.

Inclusion of chicory (Cichorium intybus L.) in pigs' diets affects the intestinal microenvironment and the gut microbiota

The content and composition of prebiotic plant fiber in the diet is important in promoting gut-related health. This study investigated the effects of the dietary inclusion of chicory forage and roots on the intestinal microenvironment of pigs. Thirty-seven-week-old pigs were fed 1 of 5 diets for 18 days, including a cereal-based control diet and 4 diets with the inclusion of 80 and 160 g kg(-1) of body weight chicory forage (CF80 and CF160), 80 g kg(-1) chicory root (CR80), and a mix of 80 g kg(-1) forage and 80 g kg(-1) chicory root (CFR). The animals maintained good performance and health irrespective of diet. Bacterial community structure and diversity in ileal and colonic samples was assessed using terminal restriction fragment length polymorphism (T-RFLP), combined with cloning and sequencing. Samples clustered perfectly according to gut segment with a higher bacterial diversity in colon than ileum. Distal ileum was dominated by lactic acid bacteria (LAB), and the relative amount of this group was increased by the CF160 and CFR diets. The colonic bacterial community was dominated by butyrate-producing bacteria and Prevotella. The increased relative abundance of butyrate-producing bacteria in the colon was positively correlated with the molar proportion of acetic acid and furthermore linked to the chicory forage diets (CF80 and CF160). Diets including chicory roots (CR80 and CFR) were correlated with a higher colonic abundance of Megasphaera elsdenii. The fermentation products and pH in digesta responded to diet type and were correlated with shifts in the microbiota, showing that chicory influences the intestinal microenvironment of pigs.

Growth performance, digestibility, and gut development of broiler chickens on diets with inclusion of chicory (Cichorium intybus L.)

A total of 256 broiler chickens (1 d old) were used in a 32-d growth trial to study the effects of chicory (Cichorium intybus L.) forage and root inclusion on growth performance, digestibility, and gut development. The chicory forage originated from 2 harvests (June and September) and was included at 60 and 120 g/kg. The chicory root was included alone at 60 g/kg or together with chicory forage, from both harvests, in equal amounts (60 g/kg). The cereal-based control diet and 7 experimental diets were fed to each of 4 pens of chickens (8 chickens/pen). A higher BW gain and lower feed conversion ratio were found at 13 d of age in chickens fed the 60 g/kg chicory forage diet (P ≤ 0.05), whereas performance did not differ between the control and 60 g/kg chicory root diets. In contrast, a lower performance and digestibility of DM, organic matter, and AME as well as a thinner cecal mucosa layer were found for the 120 g/kg chicory forage diet (P ≤ 0.05). No diet effects on organ parameters or on pH of cecum digesta were detected. The soluble nonstarch polysaccharides fractions of chicory forage did not have any major negative effects on performance and gut development, and chicory forage from the September harvest was seen to have a higher nutritional value than that from the June harvest. Thus, results from the current study suggest that chicory forage is a potentially useful fiber-rich feed ingredient with high palatability for broiler chickens.

Effects on exercise response, fluid and acid-base balance of protein intake from forage-only diets in Standardbred horses

REASON FOR PERFORMING STUDY

High-energy forage might be an alternative to concentrates for performance horses and such forage can be produced by an early cut. However, early cut forage is high in crude protein (CP), which may result in an excessive CP intake.

OBJECTIVES

To investigate how CP intake affects nitrogen (N), fluid and acid-base balance, and exercise response in horses fed high-energy forage diets. The hypothesis was that high CP intake causes acidosis, and alters fluid balance and response to intensive exercise.

METHODS

Two forage-only diets based on high-energy grass forage were fed for 23 days in a crossover design to 6 Standardbred horses in racing condition. One forage diet provided a high (HP) CP (16.6%) intake and the other diet provided recommended intake (RP) of CP (12.5%) for racehorses. The horses had intensive exercise twice and slow exercise 1-3 times every week. At the beginning and end of each period, faeces and urine were collected for 48 and 72 h, respectively and analysed for dry matter, pH and N content. At Days 19 and 23 in each period 2 race-like exercise tests were performed, a standardised treadmill test and a field test on a race track. Blood samples were taken before, during and after the tests and analysed for sodium (Na), potassium (K), chloride (CI), total plasma proteins (TPP), TCO2, urea, pH and lactate. The strong ion difference (SID) was calculated and heart rate and respiratory rate was also recorded.

RESULTS

There was a decrease in urinary pH and an increase in N excretion, blood urea, water intake, urine volume and faecal water content on the HP diet. Total water intake was higher than the increase in urinary and faecal water loss indicating increased evaporative losses on the HP diet. During the exercise tests there were no significant differences between diets in TPP, plasma lactate, blood Na, K, Cl, TCO2, pH, SID and respiratory or heart rates.

CONCLUSION

Feeding a forage-only diet with a CP intake corresponding to 160% of the requirement caused an increase in N excretion within 36-48 h after the diet was introduced and alterations in fluid and acid base balance at rest.

POTENTIAL RELEVANCE

The increased urine and probably also evaporative fluid losses suggest that feeding a HP diet will cause an unnecessary challenge for horses during prolonged exercise.

Changes in faecal bacteria associated with concentrate and forage-only diets fed to horses in training

REASONS FOR PERFORMING STUDY

Diets rich in readily fermentable carbohydrates, fed traditionally to meet the increased energy requirements of the performance horse, are associated with a number of gastrointestinal disorders that involve disturbances in the intestinal microbiota, however, these changes are poorly understood.

OBJECTIVES

With the long-term objective of improving intestinal health and to increase understanding of the relationship between diet and microbiota, the effect of feeding Standardbred horses a high-energy forage-only (F) diet was studied compared to a more traditional forage-concentrate (C) diet on faecal microbiota.

METHODS

Diets were fed in a cross-over design to 6 mature geldings on a scheduled training regime, both periods consisting of 29 days. DNA was extracted from faecal samples collected at 4 time points from each period, bacterial 16S rRNA genes were amplified and community composition assessed by terminal-restriction fragment length polymorphism, cloning and sequencing. Faecal pH and cultivable lactic acid bacteria (LAB) and enterobacteria were also assessed on the final collection day of each period.

RESULTS

Diet F resulted in a microbial composition that was more stable between sampling periods and had lower counts (P < 0.05) of cultivable LAB and specifically members of the Streptococcus bovislequinus complex. Motile and swarming Lactobacillus ruminis was present in all horses on diet C and not in horses on diet F. Diet C also resulted in the increase (P < 0.05) in members of Clostridiaceae cluster III and a concomitant reduction (P < 0.05) in an unknown group of Bacteroidales.

CONCLUSIONS AND POTENTIAL RELEVANCE

The greater microbial stability and reduction in LAB and members of the Streptococcus bovis/equinus complex on diet F indicate an opportunity to develop feeding strategies that support equine health and welfare. Novel changes identified in the faecal microbiota that resulted from carbohydrate inclusion merit further investigation.

Comparison of total tract digestibility, development of visceral organs and digestive tract of Mong cai and Yorkshire x Landrace piglets fed diets with different fibre sources

The aim of the study was to evaluate the effects of piglet age and dietary fibre source on the development of visceral organs and the gastrointestinal tract (GIT), and on growth performance and total tract apparent digestibility (TTAD) in local [pure-breed Mong cai (MC)] and exotic [Landrace x Yorkshire (LY)] piglets. The experimental diets contained different fibre sources: C (basal diet), RB (basal diet + rice bran), SPVM (basal diet + sweet potato vine meal) and CReM (basal diet + cassava residue meal). The neutral detergent fibre (NDF) content in diet C and the fibrous diets was 8.8% and 17.1%-17.7% respectively (dry matter basis). Collection of faecal samples to determine TTAD was carried out for five consecutive days before the experiment was finished (63 days). The piglets were killed at the age of 10 days (before being given the same solid feed), 30 days (weaning, 20 days after solid feed introduced) and 63 days (33 days after being given the different fibrous diets) when the length of intestinal segments, weight of organs (liver, heart, kidneys) and empty weight of the GIT (stomach, small intestine, caecum and colon + rectum) were measured. As the age of animals increased, the relative weight of organs and the length of intestines (expressed on a mass-specific basis) decreased (p < 0.05), and the weight of GIT increased (p < 0.001). The piglets fed fibrous diets had heavier GIT than those fed diet C with the highest values in CReM (p < 0.05). The colon + rectum length was not significantly different among C, RB and SPVM, but was shorter than in CReM (p < 0.05). Coefficient of total tract apparent digestibility (CTTAD) of nutrients in the fibrous diets was lower than in C (p < 0.01). Average daily gain (ADG) and feed conversion ratio (FCR) in C, RB and CReM were not different and were better than in SPVM (p < 0.01). There were no significant differences in the weights of organs between the two breeds at day 10, 30 and 63 (p > 0.05). The weight and length of GIT were not significantly different between the two breeds at day 10 and day 30, but were greater for MC at day 63. The caecum and colon + rectum at 10 and 30 days were longer in MC than in LY (p < 0.001). The relative development of GIT post-weaning was higher than pre-weaning, the difference being most apparent in MC. As a result at 63 days, MC had heavier visceral organs and GIT, and longer intestines on fibrous diets than LY (p < 0.05). The MC at 63 days had higher CTTAD of organic matter, gross energy, crude fibre and NDF (p < 0.001) and ether extract and crude protein (p < 0.05), but lower ADG and poorer FCR than LY (p < 0.001). It can be concluded that the GIT of the MC piglets developed more rapidly than LY when they were introduced to solid feed, and that the difference was more marked on the fibrous diets and after weaning, which resulted in higher total tract digestibility of nutrients in MC compared with LY. Cassava residue meal was better digested than RB and SPVM, and supported higher live weight gains.

Effects on the equine colon ecosystem of grass silage and haylage diets after an abrupt change from hay

The objective of this study was to investigate the effect of an abrupt change from grass hay (81% DM) to grass silage (36% DM) or grass haylage (55% DM), fed at similar DM intakes, and to compare the effects of silage and haylage on the composition and activities of the colon microflora. The forages were from the same swath harvested on the same day. Four adult colon-fistulated geldings were randomly assigned to diets in a crossover design. The study started with a preperiod when all 4 horses received the hay diet, followed by an abrupt feed change to the haylage diet for 2 horses and the silage diet for 2 horses. All 4 horses then had a new second preperiod of hay, followed by an abrupt feed change to the opposite haylage and silage diet. The periods were 21 d long, and the forage-only diets were supplemented with minerals and salt. The abrupt feed changes were made at 0800 h. Colon samples were taken before the abrupt feed change, 4 and 28 h after the feed change, and 8, 15, and 21 d after the feed change, all at 1200 h. Colon bacterial counts, VFA, pH, and DM concentrations were unchanged throughout the first 28 h after the abrupt feed change from hay to haylage and silage. Also, fecal pH and DM concentrations were unchanged during the first 28 h. During the weekly observations, colon lactobacilli counts increased (P = 0.023) in horses receiving the silage diet and were greater than on the haylage diet at 21 d. Streptococci counts decreased (P = 0.046) in horses receiving the haylage diet and were less than on the silage diet at 15 and 21 d. Total VFA concentrations and colon and fecal pH did not differ between diets and were unchanged throughout the weekly observations. The DM concentration of colon digesta and feces decreased (P = 0.030 and 0.049, respectively) on both diets during the weekly observations. The results suggest that in horses fed at the maintenance level of energy intake, an abrupt feed change from grass hay to grass silage or grass haylage from the same crop does not induce any major alterations in the colon ecosystem during the first 28 h. During the subsequent 3-wk period, colon and fecal DM decreased and there were alterations in the lactobacilli and streptococci bacterial counts. The changes in lactobacilli and streptococci counts need further investigation.

Effects of crude protein intake from grass silage-only diets on the equine colon ecosystem after an abrupt feed change

The objective of this study was to investigate the effect of CP intake from 2 grass silage-only diets, differing in CP concentration, fed at similar DMI on the equine colon ecosystem after an abrupt feed change between the diets. Four adult right ventral colon-fistulated geldings were fed one silage-only diet high in CP (HP, 873 g of CP/d) and one diet providing recommended intakes (RP, 615 g of CP/d). An adaptation period of 15 d on either the HP or the RP diet was followed by 2 experimental periods when the diets were fed for 22 d each in a crossover design. Colon samples were taken before and at 4, 12, and 24 h, and at 7, 14, and 22 d after the feed change. During the first 24 h after the abrupt feed change, the concentrations of total anaerobic bacteria and lactobacilli were greater on the HP than the RP diet (7.1 vs. 6.7 log(10) cfu/mL, P = 0.021, 6.0 vs. 5.5 log(10) cfu/mL, P = 0.021, respectively). During the first 24 h post feed change, VFA concentrations did not differ between the diets. From 7 to 22 d, total VFA concentrations were greater on the HP diet than on the RP diet (51.8 vs. 45.1 mmol/L, P = 0.034), and colon pH was lower on the HP diet than on the RP diet (6.9 vs. 7.2, P = 0.035). After an adaptation period of 22 d, N, ammonia, and urea concentrations and osmolality of the colon fluid did not differ between diets. Fecal pH and colon and fecal DM were unchanged throughout the experiment. The results suggest that, in horses fed at the maintenance level of energy intake, a feed change between silages with different CP content may alter the colon bacterial counts within the first 24 h. Moreover, during the subsequent 3 wk, pH decreased slightly and VFA concentrations increased, but no other major alterations occurred in the composition and activities of the colon ecosystem or fecal DM.

Digestibility and nitrogen retention of diets containing different levels of fibre in local (Mong Cai), F1 (Mong Cai x Yorkshire) and exotic (Landrace x Yorkshire) growing pigs in Vietnam

Total tract digestibility and nitrogen retention of three diets containing different levels of fibre [200, 260 and 320 g/kg neutral detergent fibre (NDF) in dry matter] were determined in three breeds of growing pig at an initial age of approximately 3.5 months. The breeds were local (Mong Cai, MC), F1 crossbred (MC x Yorkshire) and exotic (Landrace x Yorkshire, LY), allocated at random within breed (block) to double 3 x 3 Latin squares. The main fibrous ingredients of the experimental diets were rice bran, cassava residue meal and non-dehulled groundnut cake meal. Digestibility of organic matter (OM), crude protein (CP), NDF, crude fibre, gross energy (GE) and ether extract (EE) decreased as the level of dietary NDF increased (p < 0.001). The r(2) values for the relationship between NDF level and digestibility of OM, CP, GE and EE were 83%, 83%, 80% and 82% respectively. On average, an increase in NDF content of 1% unit resulted in a decrease in OM, CP, GE and EE digestibility of 0.67%, 0.75%, 0.50% and 0.42% units respectively. Digestibility of energy and nutrients was the highest for MC and the lowest for LY (p < 0.01), with intermediate values for F1. There was a negative effect of NDF level on nitrogen (N) retained as a proportion of intake (p < 0.05). Nitrogen retention and utilization were significantly higher (p < 0.001) for LY than for MC and F1 pigs.

Influence of different phosphorus levels and phytase supplementation in gestation diets on sow performance

A total of 104 sows of different parities were studied. They were fed four diets with different phosphorus (P) levels during gestation for two reproductive cycles, while the same diet was fed during lactation. The aim was to decrease the total P level in the diet during gestation and to evaluate the effect on sow performance. The gestation treatments were low P (LP-; 3.7 g P/kg feed), low P with phytase (LP+, Ronozyme P; 765 FTU/kg feed), medium P (MP; 4.5 g P/kg feed) and high P (HP; 6.0 g P/kg feed). Daily feed allowances were 2.6 kg during gestation and 9.2 kg during lactation. Number of born piglets and piglet mortality were higher (p < 0.05) in the LP treatments than in the MP and HP treatments. No difference (p > 0.05) in the numbers of live-born piglets, piglet birthweights, sow weights or piglet weight gains was found between the treatments. Phosphorus level in sow milk was the highest (p < 0.05) in the MP treatment, while no effects (p > 0.05) of treatment were found on milk Ca levels, P and Ca levels in serum of sows and piglets, nor on the analysed mineral, fat and protein contents of piglets. The estimated average requirement of P for the entire gestation period was 4.4-4.5 g/day. In conclusion, a reduction of dietary total P content during gestation did not result in negative effects on sow or piglet performance. This suggests that it should be possible to lower the dietary P content for gestating sows, compared with earlier recommendations, and thereby reduce the environmental P pollution.

Exercise response, metabolism at rest and digestibility in athletic horses fed high-fat oats

REASON FOR PERFORMING STUDY

High starch intakes increase the risk for metabolic disorders and therefore alternative feedstuffs are of interest. High-fat oat varieties have a lower starch and higher energy content than regular oats and may therefore be useful in this context.

HYPOTHESIS

Feeding high fat oats causes no adverse effects on the response to exercise and that the total amount of oats offered could be reduced compared to feeding with regular oats.

METHODS

Twelve Standardbred trotters were fed regular oats (diet C), high-fat oats (F), and a mixture (50:50) of C and F (M), together with haylage (30:70), in a Latin square design trial. High-fat oats replaced regular oats in a 0.9 to 1.0 ratio in diets F and M. On Day 18 in each 21 day experimental period, horses were subjected to a standardised near-maximal treadmill exercise test with collection of blood samples and muscle biopsies before and after exercise. This was followed by a 3 day period of total collection of faeces and urine.

RESULTS

There were no significant effects of dietary treatments on bodyweight, heart rate, plasma lactate and glucose, or on muscle glycogen and lactate concentrations following exercise. However, plasma insulin was reduced during exercise on diets F and M compared to diet C. The total tract digestibility of dry matter, fat, protein, NDF and organic matter were higher for diet F than for diet C.

CONCLUSION

High-fat oats can replace regular oats in the diet of athletic horses without any adverse effects on metabolism and exercise response.

POTENTIAL RELEVANCE

Due to the high energy content and a high digestibility of dietary components in high-fat oats the daily allowance of oats can be reduced and thus the intake of starch.

Digestive and metabolic effects of altering feeding frequency in athletic horses

The aim of this study was to investigate the effect of feeding frequency on total tract digestibility and plasma glucose, insulin, urea, gastrin and cortisol concentrations at rest and following exercise in seven Standardbred horses in race training. The horses were fed every 12 h (twice a day, 2TD) and every 4 h (six times a day, 6TD) for 25 days, in a cross-over design. The diet (64% grass hay, 36% concentrates on weight basis) was fed at twice the maintenance energy requirement. Blood samples were taken every hour for 24 h on day 17, total collection of urine and faeces was made on days 19–21 and an intensive exercise test was performed on day 25. Altering feeding frequency caused small variations in diurnal plasma glucose, urea, gastrin and cortisol concentrations and did not affect total tract nutrient digestibility. There was an increase in the mean diurnal plasma urea concentration on the 2TD regime and low levels of plasma insulin were observed 7 h after feeding 2TD. The response to intensive exercise on heart rate, plasma lactate and plasma glucose was similar on both treatments but the plasma insulin concentration was higher following exercise in the 2TD regime, indicating that post-exercise glucose metabolism was altered. In conclusion, this study shows that feeding athletic horses only 2TD caused metabolic signs resembling those observed during feed deprivation (low levels of plasma insulin and an increased diurnal plasma urea concentration) and an altered post-exercise glucose metabolism, but did not affect the digestive response.

Survey on the prevalence of diarrhoea in pre-weaning piglets and on feeding systems as contributing risk factors in smallholdings in Central Vietnam

A cross-sectional survey on the prevalence of diarrhoea in pre-weaning piglets, and on management and feeding systems under farm conditions was carried out in Thua Thien Hue Province. Faecal samples were collected from 63 piglets without, and 90 piglets with diarrhoea to determine the occurrence of Salmonella, Escherichia coli (E. coli) and different E. coli antigens (K88, K99 and 987P). The prevalence of diarrhoea was higher in the rainy season than in the dry season (33% vs 18%) and the results indicated differences in prevalence between areas. Salmonella and E. coli were found to the same extent in faeces from piglets without and with diarrhoea. All E. coli antigens were isolated from piglets without and with diarrhoea. However, the frequency was much higher in piglets suffering from diarrhoea. In piglets with diarrhoea antigen K88 was found in 26% and 20% of the samples, antigen K99 in 37% and 24% of the samples, and antigen 987P in 31% and 32% of the samples collected in the dry and rainy seasons, respectively. Nutrient supply for sows and for piglets was low in comparison with feeding standards, which may be a contributory factor to the high incidence of diarrhoea in piglets. Thus, the nutrition of sows as well as piglets could be important components in the aetiology of the disease and needs to be studied further.

Intestinal morphology and enzymatic activity in newly weaned pigs fed contrasting fiber concentrations and fiber properties

The main objective of this study was to determine the effect of fiber source and concentration on morphological characteristics, mucin staining pattern, and mucosal enzyme activities in the gastrointestinal tract of pigs. The experiment included 50 pigs from 10 litters weaned at 4 wk of age (BW 8.6 +/- 1.4 kg) and divided into 5 treatment groups. Diets containing fiber of various physico-chemical properties and concentrations were formulated to contain 73, 104, or 145 g of dietary fiber/kg of DM. The diets were based on raw wheat and barley flours. Pectin and barley hulls, representing soluble and insoluble fiber sources, respectively, were used to increase the fiber concentration. The pigs were fed the experimental diets for 9 d, and then the pigs were euthanized and the entire gastrointestinal tract was removed. Tissue samples were taken from the mid and distal small intestine and from the mid colon. Inclusion of pectin in the diets significantly decreased (P < 0.001) ADFI and ADG compared with pigs fed no pectin. The villi and the crypts were shorter in pigs fed pectin-containing diets, but the villous height/crypt depth ratio was unaltered. Pectin significantly decreased the area of mucins in the crypts of the small intestine, indicating that the pigs fed the pectin-containing diet would probably be more susceptible to pathogenic bacteria, although this cannot be separated from the impact on ADFI. The lectin-binding pattern of the intestinal mucosa was unaffected by diet. The activity of lactase and maltase was increased in pigs fed diets with high fiber content, whereas sucrase activity was increased in pigs fed the pectin-containing diets. The activity of the peptidases, aminopeptidase N and dipeptidylpeptidase IV, was increased when feeding high fiber diets, whereas the activity of gamma-glutamyl transpeptidase remained unaffected by the experimental diets. In conclusion, the reduced feed intake observed with the pectin-containing diets could explain the lower villous height and crypt depth observed in this study. However, direct effects of pectin also are possible, and thus further study is warranted. Feeding pigs high insoluble fiber diets improved gut morphology by increasing villi length and increased mucosal enzyme activity when compared with pigs fed pectin-containing diets. The mucin content as determined by staining characteristics suggests that pigs fed high insoluble fiber diets might be better protected against pathogenic bacteria than pigs fed diets high in soluble fiber.

The influence of intramammary lipopolysaccharide infusion on serum Ca, P, vitamin D, cytokines and cortisol concentrations in lactating sows

Ten multiparous lactating sows were used to investigate whether intramammary infusion of lipopolysaccharides (LPS; Escherichia coli 0111:B4; 2.0 microg/kg of body weight) would affect the circulating concentrations of Ca, P, 25-hydroxyvitamin D (25-OHD), tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and cortisol. The sows were randomly allotted to either control group (control) or LPS-treated group with five individuals per group and were infused with either physiological saline solution or LPS solution. The rectal temperature and udder quarter appearance were recorded at 0 (just before infusion), 1, 3, 7, 12 or 24 h after infusion. Blood samples were taken at 0, 1, 3, 7, 12 or 24 h after infusion. Before infusion, the rectal temperatures of all sows were below 39.2 degrees C. At 3 and 7 h after infusion, the sows in the LPS group had a rectal temperature over 39.4 degrees C. At 24 h after infusion, the rectal temperatures returned to pre-infusion levels. Serum Ca and P concentrations in the LPS group decreased (P < 0.05) after LPS infusion compared with the control group at 1 h after infusion. No significant differences (P > 0.05) in the concentrations of 25-OHD were observed between groups control and LPS at any sampling time. Increased (P < 0.01) concentrations of serum TNF-alpha, IL-6 and cortisol were observed in the LPS group compared with the control group at 3 and 7 h after infusion respectively. In conclusion, the elevation of serum concentrations of TNF-alpha, IL-6 and cortisol and the alterations of circulating concentrations of Ca and P following LPS infusion indicate that the immune system has been activated and immune activation may affect macromineral homeostatic regulation, which might have important implications for metabolic health of lactating sows. Lowered serum Ca and P following immune activation also shows a causative mechanism whereby immune activation increases the risk of secondary disorders such as mastitis-metritis-agalactia syndrome. However, immune activation did not affect circulating concentrations of vitamin D metabolites.